Pulmonary embolism workup in five steps.

A workup for pulmonary embolism (PE) is complex, with multiple clinical decision rules to remember. A proper diagnostic workup can safely rule out PE without the use of computed tomography, which is both expensive and exposes patients to radiation and intravenous contrast. However, once PE has been diagnosed, it is important to risk stratify patients according to severity to both treat and disposition them correctly. PQRsTU is a simple, easy-to-remember mnemonic for the workup of PE that considers five phases: PERC phase (PE rule-out criteria), Quantify gestalt phase (to determine proper use of D-dimer or direct to imaging), Risk stratification phase (once PE has been diagnosed), Treatment phase, and Unit or floor (patient disposition). This structured method for evaluating PE will help clinicians develop a systematic, evidence-based approach to this complex and potentially lethal disease. Video is available at https://vimeo.com/91406117 Password: perls.

Cardiovascular risk assessment of pulmonary embolism with the GRACE risk score.

Despite the existence of several risk scores, the accurate prediction of the prognosis in pulmonary embolism (PE) remains a challenge. The Global Registry of Acute Coronary Events (GRACE) risk score has a high diagnostic performance for adverse outcomes in acute coronary syndrome. We aimed to assess the applicability and extend the use of the GRACE risk score to PE. A case-control study of 206 consecutive patients admitted with PE was performed. The GRACE, Geneva, Simplified Pulmonary Embolism Severity Index, Shock Index, and European Society of Cardiology risk scores were tested for the prediction of the primary end point: all-cause 30-day mortality. Comparisons between GRACE and the other risk scores were performed using receiver operating characteristic area under the curve and the integrated discrimination improvement index. All-cause 30-day mortality was observed in 18.9% of the patients. Unlike the other classifications, no adverse outcomes were observed in patients classified as low risk using the GRACE risk score (100% negative predictive value for GRACE risk score ≤113). The GRACE score showed greater discriminative performance than the Geneva score (area under the curve 0.623, 95% confidence interval [CI] 0.53 to 0.71), Shock Index (area under the curve 0.639, 95% CI 0.55 to 0.73), European Society of Cardiology (area under the curve 0.662, 95% CI 0.57 to 0.76), and Simplified Pulmonary Embolism Severity Index (area under the curve 0.705, 95% CI 0.61 to 0.80), although statistical significance was not reached. The integrated discrimination improvement index suggested a more appropriate risk classification with the GRACE score. In conclusion, our results have demonstrated that the GRACE risk score can accurately predict 30-day mortality in patients admitted for acute PE. Compared to previously proposed PE prediction rules, the GRACE risk score presented improved overall risk classification.

Severity assessment of acute pulmonary embolism with spiral CT: evaluation of two modified angiographic scores and comparison with clinical data.

Spiral computed tomography (CT) has shown promising results in the detection of acute pulmonary embolism. The aim of this study was to investigate whether the severity of acute pulmonary embolism could be quantitatively assessed with spiral CT examinations and to test the potential clinical impact of this information. In a consecutive series of 123 patients screened with spiral CT for suspected acute pulmonary embolism, 31 patients (25%) had evidence of emboli. The severity of pulmonary arterial obstruction in those 31 spiral CT examinations was evaluated by two independent observers using angiographic scores previously described by Walsh (29) and Miller (30), adapted to the needs of spiral CT. Clinical patient subgroups were defined according to oxygen saturation, heart rate, and echocardiographic signs of right ventricular strain. CT severity scores were then correlated to each other and to clinical parameters using the Spearman rank test. Interobserver agreement was calculated using the analysis of variance. Both modified Walsh and Miller scores were readily reproducible and showed interobserver agreements of 0.85 and 0.96, respectively (p = 0.001). Patients with mild and marked clinical abnormalities showed statistically significant differences between CT severity scores. Differences between severity scores of patients with moderate and marked clinical abnormalities were somewhat significant. No significant mean severity score differences were seen between patients with mild and moderate clinical abnormalities. Although correlations of severity scores and detailed clinical parameters within the defined subgroups were moderate to poor, threshold scores greater than 10 (Miller) and greater than 11 (Walsh) always indicated marked clinical abnormalities. The modified scores presented in this study constitute a readily reproducible method for the quantitative assessment of acute pulmonary embolism severity on spiral CT examinations.

Pulmonary embolism. The implications of prospective investigation of pulmonary embolism diagnosis.

PIOPED represents a milestone in the study of pulmonary embolism diagnosis because of its well-designed protocol, proper execution, and the large number of patients enrolled. The most important conclusions of the study are 1. Interobserver agreement is good for classifying ventilation-perfusion scans either as normal or as high probability for pulmonary embolism, but interobserver agreement is lower for classifying scans as intermediate or low probability. 2. About 40% of patients with pulmonary embolism have high probability ventilation-perfusion scans, 40% have intermediate probability scans, and 20% have low probability scans. Few (less than 1%) patients with normal perfusion scans have pulmonary embolism. 3. Eighty-seven percent of patients with high probability scans have pulmonary embolism, and 30% of patients with intermediate probability scans have embolism. Unfortunately, 14% of patients with low probability scans have pulmonary embolism. 4. Clinical suspicion can be combined with the ventilation-perfusion scan results to improve the accuracy of diagnosis of pulmonary embolism. About 90% of patients with high probability scans and high or intermediate clinical suspicion for pulmonary embolism indeed have embolism. At the other extreme, only 4% of patients with both low probability scans and low clinical suspicion have embolism. In the remaining combinations of categories 6% to 66% of patients have embolism. 5. Suggested modifications of the original PIOPED criteria for classifying ventilation-perfusion scans make the analysis simpler and more useful. New studies have examined subgroups from PIOPED to refine guidelines for clinical practice further and to incorporate the results of tests for deep venous thrombosis into the diagnostic evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Stratification of patients according to prior cardiopulmonary disease and probability assessment based on the number of mismatched segmental equivalent perfusion defects. Approaches to strengthen the diagnostic value of ventilation/perfusion lung scans in acute pulmonary embolism.

A categorical diagnosis of "high probability" or "intermediate probability" encompasses a spectrum of diagnostic probabilities of pulmonary embolism (PE) that is not communicated to the referring physician. The diagnostic value of ventilation/perfusion lung scans, in the present investigation, was strengthened by use of a table to determine the likelihood of PE in individual patients on the basis of the observed number of mismatched segmental equivalent perfusion defects. In addition, we tested the hypothesis that stratification of patients according to the presence or absence of prior cardiopulmonary disease may enhance the ventilation/perfusion scan assessment of the probability of PE among both of these clinical categories of patients. Data were derived from the collaborative study of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED). Ventilation/perfusion lung scans were evaluated in 378 patients with acute PE and 672 patients in whom suspected PE was excluded. Among patients with no prior cardiopulmonary disease, > or = 1.0 mismatched segmental equivalents was indicative of PE in 102 of 118 (86 percent) vs 113 of 155 (73 percent) among patients with prior cardiopulmonary disease (p < 0.02). Among patients with prior cardiopulmonary disease, > or = 2 mismatched segmental equivalents were required to indicate > or = 80 percent probability of PE. Stratification on the basis of the presence or absence of prior cardiopulmonary disease, therefore, enhanced the ability of ventilation/perfusion scan readers to assign an accurate positive predictive value and specificity to individual patients based on the observed number of mismatched segmental equivalent defects. Among patients with no prior cardiopulmonary disease, fewer mismatched segmental equivalent defects were required to indicate a high probability of PE than were required by PIOPED criteria. The findings from some of these patients, by PIOPED criteria, would have indicated intermediate probability. Some indeterminate probability readings, therefore, will be eliminated among patients stratified with no prior cardiopulmonary disease.

The addition of clinical assessment to stratification according to prior cardiopulmonary disease further optimizes the interpretation of ventilation/perfusion lung scans in pulmonary embolism.

The purpose of this investigation was to test the hypothesis that prior clinical assessment among patients stratified according to the presence or absence of prior cardiopulmonary disease enhances the accuracy of the predictive value of pulmonary embolism (PE) in the various categories. Diagnostic evaluation was made on the cumulative spectrum of mismatched defects, rather than a probability based on a preassigned number of mismatched segmental equivalent defects or mismatched vascular defects. Families of curves were derived that allowed an accurate assessment of the predictive value for each category of patients. The families of curves were comparable, irrespective of whether ventilation/perfusion scans were assessed on the basis of mismatched segmental equivalent defects or mismatched vascular defects, although the latter eliminated the necessity of estimating whether segmental defects were large or moderate in size. Clinical assessment was shown to prominently affect the predictive value of PE. Prior clinical assessment among patients stratified according to prior cardiopulmonary disease enhanced the accuracy of the predictive value of PE in the various groups of patients.